here are two:

http://www.renderosity.com/mod/forumpro/showthread.php?message_id=3779175&ebot_calc_page#message_3779175

http://www.renderosity.com/mod/forumpro/showthread.php?message_id=3779530&ebot_calc_page#message_3779530

I prefer method one, but the part about animating the transmap  ... you would want a procedural, but IMVHO turbulence is not a good method.  I tried "spots" but it was too lousy to even post.  keep asking them about how to animate the transmap.

p.s. in resp. to steve, OP animated z-scale on turb., but no function plugged into it, hence OP may have typed values in key frames (not best IMVHO).